The common belief fallacy occurs when people assert that a statement is true just because many other people are saying it is true and not because there is any proof that it is true (Messina and Messina, 2005). People believe what is said because everyone else believes it, rather than checking for themselves whether or not it is true. When people are uncertain about something, they often look at what the people around them, or their friends, or just people in general, are saying about it and they go along with what most people seem to think (Appeal, 2005). For instance, in advertising, a drug company will often say something like, "9 out of 10 doctors recommend brand x pain reliever for headaches" so people believe that it must be good because most doctors recommend it. They don't bother to see if an actual study was done and which doctors said they would recommend the drug, or how many doctors were actually interviewed - 10 or 10,000. They don't check the facts, they just go along with what they think most people believe. The more people who believe something is true, the more an individual will be likely to believe it because no one likes to be alone - they like to be part of those "in the know." If people hear that a particular car is the most popular in America, or the most reliable, they will believe it if they think a lot of people also believe it, and will buy it because everyone else is buying it. They don't look for the actual truth, just popular opinion, and trust that someone has already checked out the facts and found them to be true.